There are 2 major categories of IUGR: symmetrical and asymmetrical. Some conditions are associated with both symmetrical and asymmetrical growth restriction.

Asymmetrical IUGR is more common (70%). In asymmetrical IUGR, there is restriction of weight followed by length. The head continues to grow at normal or near-normal rates (head sparing). A lack of subcutaneous fat leads to a thin and small body out of proportion with the liver. Normally at birth the brain of the fetus is 3 times the weight of its liver. In IUGR, It becomes 5-6 times. In these cases, the embryo/fetus has grown normally for the first two trimesters but encounters difficulties in the third, sometimes secondary to complications such as pre-eclampsia. Other symptoms than the disproportion include dry, peeling skin and an overly-thin umbilical cord. The baby is at increased risk of hypoxia and hypoglycaemia. This type of IUGR is most commonly caused by extrinsic factors that affect the fetus at later gestational ages. Specific causes include:

- Chronic high blood pressure

- Severe malnutrition

- Genetic mutations, Ehlers–Danlos syndrome

Low birth weight (LBW) is defined by the World Health Organization as a birth weight of a

infant of 2,499 g or less, regardless of gestational age. Subcategories include very low birth weight (VLBW), which is less than 1500 g (3 pounds 5 ounces), and extremely low birth weight (ELBW), which is less than 1000 g (2 pounds 3 ounces). Normal weight at term delivery is 2500–4200 g (5 pounds 8 ounces – 9 pounds 4 ounces).

LBW is either caused by preterm birth (that is, a low gestational age at birth, commonly defined as younger than 37 weeks of gestation) or the infant being small for gestational age (that is, a slow prenatal growth rate), or a combination of both.

In general, risk factors in the mother that may contribute to low birth weight include young ages, multiple pregnancies, previous LBW infants, poor nutrition, heart disease or hypertension, untreated coeliac disease, drug addiction, alcohol abuse, and insufficient prenatal care. Environmental risk factors include smoking, lead exposure, and other types of air pollutions.

Each year, ill health as a result of pregnancy is experienced (sometimes permanently) by more than 20 million women around the world. In 2013 complications of pregnancy resulted in 293,000 deaths down from 377,000 deaths in 1990. Common causes include maternal bleeding (44,000), complications of abortion (44,000), high blood pressure of pregnancy (29,000), maternal sepsis (24,000), and obstructed labor (19,000).

The following are some examples of pregnancy complications:

- Pregnancy induced hypertension

- Anemia

- Postpartum depression

- Postpartum psychosis

- Thromboembolic disorders. These are the leading cause of death in pregnant women in the US.

- PUPPP (Pruritic Urticarial Papules and Plaques of Pregnancy), a skin disease that develops around the 32nd week. Signs are red plaques, papules, and itchiness around the belly button that then spreads all over the body except for the inside of hands and face.

- Ectopic pregnancy, implantation of the embryo outside the uterus.

- Hyperemesis gravidarum, excessive nausea and vomiting that is more severe than normal morning sickness.

- Pulmonary embolism, blood clots that form in the legs that can migrate to the lungs.

There is also an increased susceptibility and severity of certain infections in pregnancy.

Generally it is preferable to describe specific signs in lieu of declaring "fetal distress" that include:

- Decreased movement felt by the mother

- Meconium in the amniotic fluid ("meconium stained fluid")

- Non-reassuring patterns seen on cardiotocography:

- increased or decreased fetal heart rate (tachycardia and bradycardia), especially during and after a contraction

- decreased variability in the fetal heart rate

- late decelerations

- Biochemical signs, assessed by collecting a small sample of baby's blood from a scalp prick through the open cervix in labor

- fetal metabolic acidosis

- elevated fetal blood lactate levels (from fetal scalp blood testing) indicating the baby has a lactic acidosis

Some of these signs are more reliable predictors of fetal compromise than others. For example, cardiotocography can give high false positive rates, even when interpreted by highly experienced medical personnel. Metabolic acidosis is a more reliable predictor, but is not always available.

The symptoms and discomforts of pregnancy are those presentations and conditions that result from pregnancy but do not significantly interfere with activities of daily living or pose a threat to the health of the mother or baby. This is in contrast to pregnancy complications. Sometimes a symptom that is considered a discomfort can be considered a complication when it is more severe. For example, nausea (morning sickness) can be a discomfort, but if, in combination with significant vomiting it causes a water-electrolyte imbalance, it is a complication known as hyperemesis gravidarum.

Common symptoms and discomforts of pregnancy include:

- Tiredness.

- Constipation

- Pelvic girdle pain

- Back pain

- Braxton Hicks contractions. Occasional, irregular, and often painless contractions that occur several times per day.

- Edema (swelling). Common complaint in advancing pregnancy. Caused by compression of the inferior vena cava and pelvic veins by the uterus leads to increased hydrostatic pressure in lower extremities.

- Increased urinary frequency. A common complaint, caused by increased intravascular volume, elevated glomerular filtration rate, and compression of the bladder by the expanding uterus.

- Urinary tract infection

- Varicose veins. Common complaint caused by relaxation of the venous smooth muscle and increased intravascular pressure.

- Haemorrhoids (piles). Swollen veins at or inside the anal area. Caused by impaired venous return, straining associated with constipation, or increased intra-abdominal pressure in later pregnancy.

- Regurgitation, heartburn, and nausea.

- Stretch marks

- Breast tenderness is common during the first trimester, and is more common in women who are pregnant at a young age.

In addition, pregnancy may result in pregnancy complication such as deep vein thrombosis or worsening of an intercurrent disease in pregnancy.

In medicine (obstetrics), the term fetal distress refers to the presence of signs in a pregnant woman—before or during childbirth—that suggest that the fetus may not be well. Because of its lack of precision, the term is eschewed in modern American obstetrics.

In terms of FASD, growth deficiency is defined as significantly below average height, weight or both due to prenatal alcohol exposure, and can be assessed at any point in the lifespan. Growth measurements must be adjusted for parental height, gestational age (for a premature infant), and other postnatal insults (e.g., poor nutrition), although birth height and weight are the preferred measurements. Deficiencies are documented when height or weight falls at or below the 10th percentile of standardized growth charts appropriate to the population.

Criteria for FASD are least specific in the IOM diagnostic system ("low birth weight..., decelerating weight not due to nutrition..., [or] disproportional low weight to height" p. 4 of executive summary), while the CDC and Canadian guidelines use the 10th percentile as a cut-off to determine growth deficiency. The "4-Digit Diagnostic Code" allows for mid-range gradations in growth deficiency (between the 3rd and 10th percentiles) and severe growth deficiency at or below the 3rd percentile. Growth deficiency (at severe, moderate, or mild levels) contributes to diagnoses of FAS and pFAS, but not ARND or static encephalopathy.

Growth deficiency is ranked as follows by the "4-Digit Diagnostic Code":

- Severe: Height and weight at or below the 3rd percentile.

- Moderate: Either height or weight at or below the 3rd percentile, but not both.

- Mild: Either height or weight or both between the 3rd and 10th percentiles.

- None: Height and weight both above the 10th percentile.

In the initial studies that discovered FAS, growth deficiency was a requirement for inclusion in the studies; thus, all the original people with FAS had growth deficiency as an artifact of sampling characteristics used to establish criteria for the syndrome. That is, growth deficiency is a key feature of FASD because growth deficiency was a criterion for inclusion in the study that defined FAS. This suggests growth deficiency may be less critical for understanding the disabilities of FASD than the neurobehavioral sequelae to the brain damage.

Other conditions may commonly co-occur with FAS, stemming from prenatal alcohol exposure. However, these conditions are considered alcohol-related birth defects and not diagnostic criteria for FAS.

- Heart: A heart murmur that frequently disappears by one year of age. Ventricular septal defect most commonly seen, followed by an atrial septal defect.

- Bones: Joint anomalies including abnormal position and function, altered palmar crease patterns, small distal phalanges, and small fifth fingernails.

- Kidneys: Horseshoe, aplastic, dysplastic, or hypoplastic kidneys.

- Eyes: Strabismus, optic nerve hypoplasia (which may cause light sensitivity, decreased visual acuity, or involuntary eye movements).

- Occasional problems: ptosis of the eyelid, microophthalmia, cleft lip with or without a cleft palate, webbed neck, short neck, tetralogy of Fallot, coarctation of the aorta, spina bifida, and hydrocephalus.

A vanishing twin, also known as fetal resorption, is a fetus in a multi-gestation pregnancy which dies in utero and is then partially or completely reabsorbed. In some instances, the dead twin will be compressed into a flattened, parchment-like state known as "fetus papyraceus".

Vanishing twins occur in up to one out of every eight multifetus pregnancies and may not even be known in most cases. "High resorption rates, which cannot be explained on the basis of the expected abortion rate...suggest intense fetal competition for space, nutrition, or other factors during early gestation, with frequent loss or resorption of the other twin(s)."

In pregnancies achieved by IVF, "it frequently happens that more than one amniotic sac can be seen in early pregnancy, whereas a few weeks later there is only one to be seen and the other has 'vanished'."

Slowed growth is well documented in fetuses, but it is not as clear whether older children remain smaller or catch up to their peers. Some studies show that growth remains slowed for as many as ten years. PCE may also interfere with the way the motor system matures. Motor effects that have been documented include poorer reflexes and quality of movement in infants. PCE may have an effect on the neuroendocrine system, but more study is needed to determine whether it does and what the effects are.

A review of the literature reported that cocaine use causes congenital defects between 15 and 20% of the time; however another large-scale study found no difference in rates of birth anomalies in PCE and non-PCE infants. It has been suggested that some birth defects could be due to cocaine's disruption of blood vessel growth.

Most PCE-related congenital defects are found in the brain, heart, genitourinary tract, arms and legs.

Cocaine use by pregnant mothers may directly or indirectly contribute to defects in the formation of the circulatory system and is associated with abnormalities in development of the aorta. Heart malformations can include a missing ventricle and defects with the septum of the heart, and can result in potentially deadly congestive heart failure. Genital malformations occur at a higher-than-normal rate with PCE.

The liver and lungs are also at higher risk for abnormalities. Cloverleaf skull, a congenital malformation in which the skull has three lobes, the brain is deformed, and hydrocephalus occurs, is also associated with PCE. Like birth defects, small head size, and stroke are risks in PCE.

Cocaine use during pregnancy can be discovered by asking the mother, but sometimes women will not admit to having used drugs. Mothers may lie for fear of prosecution or having their children taken away, but even when they are willing to tell the truth their memories may not be very accurate. It may also not be possible to be sure of the purity of the drug they have taken. More reliable methods for detecting cocaine exposure involve testing the newborn's hair or meconium (the infant's earliest stool). Hair analysis, however, can give false positives for cocaine exposure, and a newborn may not have enough hair to test. The newborn's urine can be tested for cocaine and metabolites, but it must be collected as soon as possible after birth. It is not known how long after exposure the markers will still show up in a newborn's urine. The mother's urine can also be tested for drugs, but it cannot detect drugs used too far in the past or determine how much or how often the drugs were used. Tests cannot generally detect cocaine use over a week prior to sample collection. Mothers are more honest about cocaine use when their urine is also tested, but many users still deny it. Both maternal and neonatal urine tests can give false negatives.

In most cases Ballantyne syndrome causes fetal or neonatal death and in contrast, maternal involvement is limited at the most to preeclampsia.

Protein–energy malnutrition (PEM) refers to a form of malnutrition which is defined as a range of pathological conditions arising from coincident lack of protein and/or energy in varying proportions.The condition vary in forms ranging from mild through moderate to severe degrees.

Types include:

- Kwashiorkor (protein malnutrition predominant)

- Marasmus (deficiency in calorie intake)

- Marasmic Kwashiorkor (marked protein deficiency and marked calorie insufficiency signs present, sometimes referred to as the most severe form of malnutrition)

PEM is fairly common worldwide in both children and adults and accounts for 6 million deaths annually. In the industrialized world, PEM is predominantly seen in hospitals, is associated with disease, or is often found in the elderly.

Note that PEM may be secondary to other conditions such as chronic renal disease or cancer cachexia in which protein energy wasting may occur.

Protein–energy malnutrition affects children the most because they have less protein intake. The few rare cases found in the developed world are almost entirely found in small children as a result of fad diets, or ignorance of the nutritional needs of children, particularly in cases of milk allergy.

Mirror syndrome or triple oedema or Ballantyne syndrome is a rare disorder affecting pregnant women. It describes the unusual association of fetal

and placental hydrops with maternal preeclampsia.

The name "mirror syndrome" refers to the similarity between maternal oedema and fetal hydrops. It was first described in 1892 by John William Ballantyne.

An intercurrent (or concurrent, concomitant or, in most cases, pre-existing) disease in pregnancy is a disease that is not directly caused by the pregnancy (in contrast to a complication of pregnancy), but which may become worse or be a potential risk to the pregnancy (such as "causing" pregnancy complications). A major component of this risk can result from necessary use of drugs in pregnancy to manage the disease.

In such circumstances, women who wish to continue with a pregnancy require extra medical care, often from an interdisciplinary team. Such a team might include (besides an obstetrician) a specialist in the disorder and other practitioners (for example, maternal-fetal specialists or obstetric physicians, dieticians, etc.).

When vomiting is severe it may result in the following:

- Loss of 5% or more of pre-pregnancy body weight

- Dehydration, causing ketosis, and constipation

- Nutritional disorders such as vitamin B1 (thiamine) deficiency, vitamin B6 deficiency or vitamin B12 deficiency

- Metabolic imbalances such as metabolic ketoacidosis or thyrotoxicosis

- Physical and emotional stress of pregnancy on the body

- Difficulty with activities of daily living

Symptoms can be aggravated by hunger, fatigue, prenatal vitamins (especially those containing iron), and diet. Many people with HG are extremely sensitive to odors in their environment; certain smells may exacerbate symptoms. Excessive salivation, also known as sialorrhea gravidarum, is another symptom experienced by some women.

Hyperemesis gravidarum tends to occur in the first trimester of pregnancy and lasts significantly longer than morning sickness. While most women will experience near-complete relief of morning sickness symptoms near the beginning of their second trimester, some sufferers of HG will experience severe symptoms until they give birth to their baby, and sometimes even after giving birth.

A small percentage rarely vomit, but the nausea still causes most (if not all) of the same issues that hyperemesis with vomiting does.

Protein malnutrition is detrimental at any point in life, but protein malnutrition prenatally has been shown to have significant lifelong effects. During pregnancy, one should aim for a diet that consists of at least 20% protein for the health of the fetus. Diets that consist of less than 6% protein "in utero" have been linked with many deficits, including decreased brain weight, increased obesity, and impaired communication within the brain in some animals. Even diets of mild protein malnutrition (7.2%) have been shown to have lasting and significant effects in rats. The following are some studies in which prenatal protein deficiency has been shown to have unfavorable consequences.

- Decreased brain size: Protein deficiency has been shown to affect the size and composition of brains in rhesus monkeys. Monkeys whose mother had eaten a diet with an adequate amount of protein were shown to have no deficit in brain size or composition, even when their body weight amounted to less than one-half of that of the controls, whereas monkeys whose mothers had eaten low-protein diets were shown to have smaller brains regardless of the diet given after birth.

- Impaired neocortical long-term potentiation: Mild protein deficiency (in which 7.2% of the diet consists of protein) in rats has been shown to impair entorhinal cortex plasticity (visuospatial memory), noradrenergic function in the neocortex, and neocortical long-term potentiation.

- Altered fat distribution: Protein undernutrition can have varying effects depending on the period of fetal life during which the malnutrition occurred. Although there were not significant differences in the food intake, there were increased amounts of perirenal fat in rats that were protein-deprived during early (gestation days 0–7) and mid (gestation days 8–14) pregnancy, and throughout pregnancy, whereas rats that were protein-deprived only late in gestation (gestation days 15–22) were shown to have increased gonadal fat.

- Increased obesity: Mice exposed to a low-protein diet prenatally weighed 40% less than the control group at birth (intrauterine growth retardation). When fed a high-fat diet after birth, the prenatally undernourished mice were shown to have increased body weight and adiposity (body fat), while those who were adequately nourished prenatally did not show an increase in body weight or adiposity when fed the same high-fat diet after birth.

- Decreased birth weight, and gestation duration: Supplementation of protein and energy can lead to increased duration of gestation and higher birth weight. When fed a supplement containing protein, energy, and micronutrients, pregnant women showed more successful results during birth, including high birth weights, longer gestations, and fewer pre-term births, than women who had consumed a supplement with micronutrients and low energy but no protein (although this finding may be due to the increase of energy in the supplements, not the increase of protein).

- Increased stress sensitivity: Male offspring of pregnant rats fed low-protein diets have been shown to exhibit blood pressure that is hyperresponsive to stress and salt.

- Decreased sperm quality: A low-protein diet during gestation in rats has been shown to affect the sperm quality of the male offspring in adulthood. The protein deficiency appeared to reduce sertoli cell number, sperm motility, and sperm count.

- Altered cardiac energy metabolism: Prenatal nutrition, specifically protein nutrition, may affect the regulation of cardiac energy metabolism through changes in specific genes.

- Increased passive stiffness: Intrauterine undernutrition was shown to increase passive stiffness in skeletal muscles in rats.

From these studies it is possible to conclude that prenatal protein nutrition is vital to the development of the fetus, especially the brain, the susceptibility to diseases in adulthood, and even gene expression. When pregnant females of various species were given low-protein diets, the offspring were shown to have many deficits. These findings highlight the great significance of adequate protein in the prenatal diet.

Diabetes mellitus and pregnancy deals with the interactions of diabetes mellitus (not restricted to gestational diabetes) and pregnancy. Risks for the child include miscarriage, growth restriction, growth acceleration, fetal obesity (macrosomia), polyhydramnios and birth defects.

Meronanencephaly is a rare form of anencephaly characterized by malformed cranial bones, a median cranial defect, and a cranial protrusion called area cerebrovasculosa. Area cerebrovasculosa is a section of abnormal, spongy, vascular tissue admixed with glial tissue ranging from simply a membrane to a large mass of connective tissue, hemorrhagic vascular channels, glial nodules, and disorganized choroid plexuses.

The most common type of anencephaly, where the brain has entirely failed to form, except for the brain stem. Infants rarely survive more than one day after birth with holoanencephaly.

Hyperemesis gravidarum (HG) is a pregnancy complication that is characterized by severe nausea, vomiting, weight loss, and possibly dehydration. Signs and symptoms may also include vomiting several times a day and feeling faint. Hyperemesis gravidarum is considered more severe than morning sickness. Often symptoms get better after the 20th week of pregnancy but may last the entire pregnancy duration.

The exact causes of hyperemesis gravidarum are unknown. Risk factors include the first pregnancy, multiple pregnancy, obesity, prior or family history of HG, trophoblastic disorder, and a history of eating disorders. Diagnosis is usually made based on the observed signs and symptoms. HG has been technically defined as more than three episodes of vomiting per day such that weight loss of 5% or three kilograms has occurred and ketones are present in the urine. Other potential causes of the symptoms should be excluded including urinary tract infection and high thyroid levels.

Treatment includes drinking fluids and a bland diet. Recommendations may include electrolyte-replacement drinks, thiamine, and a higher protein diet. Some women require intravenous fluids. With respect to medications pyridoxine or metoclopramide are preferred. Prochlorperazine, dimenhydrinate, or ondansetron may be used if these are not effective. Hospitalization may be required. Psychotherapy may improve outcomes. Evidence for acupressure is poor.

While vomiting in pregnancy has been described as early as 2,000 BC, the first clear medical description of hyperemesis gravidarum was in 1852 by Antoine Dubois. Hyperemesis gravidarum is estimated to affect 0.3–2.0% of pregnant women. While previously known as a common cause of death in pregnancy, with proper treatment this is now very rare. Those affected have a low risk of miscarriage but a higher risk of premature birth. Some pregnant women choose to have an abortion due to HG's symptoms.

Tricho-hepato-enteric syndrome is one particular form of intractable diarrhea of infancy, presenting typically in the first month of life. These babies were usually born small for their age and continue to experience failure to thrive, usually with a final short stature. Typical facial features include prominent forehead and cheeks, a broad nasal root and widely spaced eyes (hypertelorism). Their hairs are woolly, easily removed and poorly pigmented. Liver disease is mainly present as cirrhosis or fibrosis, and staining might reveal high iron content of the liver cells (consistent with hemochromatosis). Most evaluated patients had some degree of decrease in intelligence.

List of types of malnutrition or list of nutritional disorders include diseases that results from excessive or inadequate intake of food and nutrients. They come in two broad categories: undernutrition and overnutrition.